21221123 has 8 divisors (see below), whose sum is σ = 26457600. Its totient is φ = 16535880.

The previous prime is 21221113. The next prime is 21221129. The reversal of 21221123 is 32112212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21221123 - 2⁸ = 21220867 is a prime.

It is a super-2 number, since 2×21221123² = 900672122762258, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21221098 and 21221107.

It is not an unprimeable number, because it can be changed into a prime (21221129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 137723 + ... + 137876.

It is an arithmetic number, because the mean of its divisors is an integer number (3307200).

Almost surely, 2^21221123 is an apocalyptic number.

21221123 is a deficient number, since it is larger than the sum of its proper divisors (5236477).

21221123 is a wasteful number, since it uses less digits than its factorization.

21221123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275617.

The product of its digits is 48, while the sum is 14.

The square root of 21221123 is about 4606.6390134240. The cubic root of 21221123 is about 276.8573903062.

Adding to 21221123 its reverse (32112212), we get a palindrome (53333335).

The spelling of 21221123 in words is "twenty-one million, two hundred twenty-one thousand, one hundred twenty-three".